TEHRAN (FNA)- Local sources in Eastern Syria said that several Russian military advisors have been killed in the US-led coalition air raid in Eastern Deir Ezzur.

Local sources told Iran's Tasnim news agency that three pro-government Hezbollah forces, several tribal fighters and several Russian military advisors were killed in the US raid in Khasham gas field in Eastern Deir Ezzur.

The US-led coalition fighter jets carried out heavy bombardment in an energy-rich region on the Eastern bank of the Euphrates River on Wednesday.

The Russian Defense Ministry had earlier announced that the Russian military men were not in the region on the Eastern Bank of the Euphrates River that came under US air attack.

In the meantime, the Russia-run Humeimim Airbase in Western Syria announced via its Central network that the US air attack on the Syrian Army troops' positions in Eastern Deir Ezzur was aimed at destabilizing the region.

The Russian military in Humeimim airbase in the coastal province of Lattakia further added the US-led collation attacks on the Syrian government forces are unjustifiable.

The coalition forces claim that they are in the region to battle against the ISIL, but their operation, especially their recent attack on the pro-government forces' positions only 8 km away from the de-escalation regions' line near the Euphrates River proved that the claims are not true.

On Wednesday, the US-led alliance said it carried out air strikes against pro-government forces after they launched an “unprovoked attack” on the headquarters of the US-backed SDF.

The statement also claimed that the US-led attack was “in self-defense.”

Reuters later cited a US official as saying on condition of anonymity that over 100 pro-government forces had been killed in the assault.

The US has around 2,000 military personnel in Northern Syria supporting the SDF, which is an alliance of militias in northern and eastern Syria and largely dominated by the Kurdish People’s Protection Units (YPG).

The US and its allies have been bombarding what they call ISIL positions inside Syria since September 2014 without any authorization from the Damascus government or a UN mandate.

The strikes, however, have on many occasions resulted in civilian casualties and failed to fulfill their declared aim of countering terrorism.

The Syrian Foreign Ministry has on several occasions written to the UN, complaining that the US is flagrantly violating the sovereignty of Syria by targeting residential neighborhoods.

Don't know if this is true bit if it is a red line has been crossed,if this isn't a red line what the F.. is?